At a friend's request I've made a video of my Giant Asian pond turtles eating tomatoes.
They're struggling but I help them a little bit by holding the tomatoes.
I usually keep these turtles separated because they can't get along. Around 1:40 in the video I intervened when they were about to bite each other. You can actually hear them hissing.
Enjoy! http://www.youtube.com/watch?v=5EKwmK0P7yg